lethargic hamster

[Becca]

Hi I'm new here and have a lovely syrian, Hamlet.
I only got him 2 months ago but get very paranoid about him as I have grown quite attached already, and worry a lot about nothing. But once again I am worrying...
Not last night but the night before he somehow escaped, luckily I found him a few hours later in a cupboard. Last night he stayed in bed til around 3am, I was hoping he was just tired from his adventure but he hasn't been out much today either.
He has popped out to pee and have a bit of food, and I gave him some lettuce but I haven't seen him drink (hopefully he has but I have missed it).
But usually he is much more active than this so I am worrying!
Can anyone think of a reason why he is being like this? He has a very nice cage and lots to do, I feed him well and give him fresh water each day, so he has no reason to be acting this way